Geog Midterm 1
Card Set Information
Geog Midterm 1
Chapters 1 to 3 for Geog midterm 1
What are the evidence of sphericity?
-Photos rom moon, earth orbit, satellite images.
-Disapperance of ships over the horizon
-Shadow of earth on moon during an eclipse
-Pythagoras (587-507 BC) concluded that the eart was sphere revolving on a fixed point.
Who is Eratosthenes?
He calculated the earth's polar circumfernce using simple geometic principles.
What is Syene?
City near tropic of Cancer. Which has no shadow at noon on the longest day.
How did Eratosthenes calculate earth's polar circumference?
Eratosthenes compared city of Syene and Alexandria on longest day. Alexandria on longest day shadow is 7.2 degrees.
What is a geoid?
Oblong 3D shape that resembles a sphere.
What shape is the earth?
A geoid. [bulges at the equator]
What is latitude?
Angular distance from equator to North and South Pole.
What is longitude?
Angular distance from Prime Meridian to East and West.
How are latitude and longitude measured?
Degrees, minutes and seconds.
Where is the Prime Meridian?
Greenwich, England at Royal Observatory.
What is the International Dateline?
180 degrees east or west from Prime Meridian. It divides the globe into different days.
What are great circles?
A plane intersecting the globe along a great cirlce divides the globe into equal halves and passes through the center.
What are small circles?
A plan that splits the globe into unequal sections and does not pass through the center of the globe.
What are parallels?
A line connecting points along the same latitude. Parallels get shorter toward the poles.
What is the equator?
The equator is the longest parallel and is also a great circle. The only great circle that is a latitude measure. Angle measure of the equator is 0 degrees.
How many degrees of longitude or latitude is an hour?
What are the different types of map projection representations?
What does an equidistant map projection portray?
Accurately portrays distances from the center of the projection to another place on the map.
What does an azmuthal map projection portray?
What does an equal area map projection portray?
Areas that have the same proportional relationship.
What does a conformal map projection portray?
Shape; map scale is the same in any direction.
What is a proximal map?
When the relationship between distance on a map and the same distance on the earth is preserved.
What is a Mercator Projection?
Cylindrical map that is conformal, but area at higher latitudes are distorted. Rhumb lines are portrayed as straight lines.
Describe Albers Equal Area Projection
Areas portrayed accurately, but shapes are distorted.
Describe Planar Projections (gnomonic)
Created by projecting the earth's image onto a flat plane. Great circles are projected as straight lines.
Describe Oval Projections (Robinson)
Created using complex calculations rather than the purely physical approach. Represents a compromise between equal area and true shape.
What are rhumb lines?
Lines of constant heading or direction.
What are two properties of rhumb lines?
Look like straight lines on Mercator projection [Great circle lines look curved]. And opposite on gnomonic projection.
What does GPS stand for?
Global Positioning System
How does GPS work?
Calculates position by measuring the distance between itself and three or more satellites. [Time delay for the signal to travel] Microwave signals used.
What are the two types of Remote Sensing?
Active RS and Passive RS
What is Active RS?
Direct energy at the earth, by the sensor, and observe the character of the energy reflected back to the remote sensing platform.
What is Passive RS?
Record the character energy radiated from the earth's surface (no energy is emitted by the sensor)
What is GIS?
Geographic Information Systems
What are GIS used for?
This computer software system organizes spatial information and produces digital maps in layers that can be combined of viewed separately.
What is Perihelion?
Earth's closest position to the sun during its orbit.
What is Aphelion?
Earth's furthest position from the sun during its orbit.
Five reasons for seasons:
Revolution, Rotation, Tilt, Axial Parallelism, and Sphericity.
Dates of season change:
Winter Solstice; December 21-22
Vernal Equinox; March 20-21
Summer Solstice; June 20-21
Autumnal Equinox; September 22-23
What is fusion?
The process where superheated atoms of hydrogen are forced together.
What is solar wind?
Gaseous flow of energy that flows out from the sun.
Describe the relationship between wavelength and energy.
Shorter wavelength means more energy is being emitted.
What does insolation mean?
Intercepted Solar Radition
What is transmission?
The passage of energy through the atmosphere or water.
What is the solar constant?
The average value of insolation at the thermopause: 1,372 W/m
Four paths solar radiation can take:
Scattering, refraction, reflection, or absorption
What is albedo?
The measure of reflectivity an object has.
What is Net Radiation?
The final outcome of radiation of earth's surface.
[(+SW) + (-SW)] + [(+LW) + (-LW)] = Net R
What are some temperature controls?
Latitude, altitude, cloud cover, and land-water heating.
What is the Continental Effect?
Inland locations have greater range in daily and seasonal temperatures because land is a better conductor for heat.
What is the Maritime Effect?
Coastal locations have a smaller range in daily and seasonal temperatures because ocean helps regulate heat.
What are isotherms?
Lines of equal temperatures on a map.